title: Cardiac autonomic modulation is determined by gender and is independent of aerobic physical capacity in healthy subjects.
abstract: BACKGROUND
  Aerobic physical capacity plays an important role in reducing morbidity and mortality rates in subjects with cardiovascular diseases. This action is often related to an improvement in the autonomic modulation of heart rate variability (HRV). However, controversies remain regarding the effects of physical training on cardiac autonomic control in healthy subjects. Therefore, our objective was to investigate whether aerobic capacity interferes with the autonomic modulation of HRV and whether gender differences exist.
  
  
  METHODS
  Healthy men and women (N=96) were divided into groups according to aerobic capacity: low (VO2: 22-38 ml/kg(-1) min(-1)), moderate (VO2: 38-48 ml/kg(-1) min(-1)) and high (VO2 >48 ml/kg(-1) min(-1).) We evaluated the hemodynamic parameters and body composition. The autonomic modulation of HRV was investigated using spectral analysis. This procedure decomposes the heart rate oscillatory signal into frequency bands: low frequency (LF=0.04-0.15Hz) is mainly related to sympathetic modulation, and high frequency (HF=0.15-0.5Hz) corresponds to vagal modulation.
  
  
  RESULTS
  Aerobic capacity, regardless of gender, determined lower values of body fat percentage, blood pressure and heart rate. In turn, the spectral analysis of HRV showed that this parameter did not differ when aerobic capacity was considered. However, when the genders were compared, women had lower LF values and higher HF values than the respective groups of men.
  
  
  CONCLUSIONS
  The results suggest that aerobic physical capacity does not interfere with HRV modulation; however, the cardiac modulatory balance differs between genders and is characterized by a greater influence of the autonomic vagal component in women and by the sympathetic component in men.
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Sabrina G V
authors.initials: SG
authors.lastname: Dutra
authors.forename: Ana Paula M
authors.initials: AP
authors.lastname: Pereira
authors.forename: Geisa C S V
authors.initials: GC
authors.lastname: Tezini
authors.forename: José H
authors.initials: JH
authors.lastname: Mazon
authors.forename: Marli C
authors.initials: MC
authors.lastname: Martins-Pinge
authors.forename: Hugo C D
authors.initials: HC
authors.lastname: Souza
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure; D001823:Body Composition; D015444:Exercise; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D012737:Sex Factors; D013564:Sympathetic Nervous System / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology*